From 94caefa2cd75a47965529c1a53844a7dfaba5d0c Mon Sep 17 00:00:00 2001
From: Rishabh Shukla <42492389+blurry-x-face@users.noreply.github.com>
Date: Thu, 16 Jan 2020 23:17:55 +0530
Subject: [PATCH] Contrast module now uses changePixel Method (#1482)

* contrast module uses changePixel Method

* change if block to Math function

* fix bug

Co-authored-by: Harsh Khandeparkar <34770591+HarshKhandeparkar@users.noreply.github.com>
Co-authored-by: Jeffrey Warren <jeff@unterbahn.com>
---
 src/modules/Contrast/Contrast.js | 30 ------------------------------
 src/modules/Contrast/Module.js   | 26 ++++++++++++++++++++++----
 2 files changed, 22 insertions(+), 34 deletions(-)
 delete mode 100644 src/modules/Contrast/Contrast.js

diff --git a/src/modules/Contrast/Contrast.js b/src/modules/Contrast/Contrast.js
deleted file mode 100644
index 1be556d4..00000000
--- a/src/modules/Contrast/Contrast.js
+++ /dev/null
@@ -1,30 +0,0 @@
-var _ = require('lodash');
-const pixelSetter = require('../../util/pixelSetter.js');
-
-module.exports = exports = function(pixels, contrast) {
-  let oldpix = _.cloneDeep(pixels);
-  contrast = Number(contrast);
-  if (contrast < -100) contrast = -100;
-  if (contrast > 100) contrast = 100;
-  contrast = (100.0 + contrast) / 100.0;
-  contrast *= contrast;
-
-  for (let i = 0; i < pixels.shape[0]; i++) {
-    for (let j = 0; j < pixels.shape[1]; j++) {
-            
-      var rgbarray = [oldpix.get(i, j, 0) / 255.0, oldpix.get(i, j, 1) / 255.0, oldpix.get(i, j, 2) / 255.0];
-      for(var idx = 0;idx < 3;idx++){
-        rgbarray[idx] -= 0.5;
-        rgbarray[idx] *= contrast;
-        rgbarray[idx] += 0.5;
-        rgbarray[idx] *= 255;
-        if (rgbarray[idx] < 0) rgbarray[idx] = 0;
-        if (rgbarray[idx] > 255) rgbarray[idx] = 255;
-      }
-            
-      pixelSetter(i, j, rgbarray, pixels);
-            
-    }
-  }
-  return pixels;
-};
\ No newline at end of file
diff --git a/src/modules/Contrast/Module.js b/src/modules/Contrast/Module.js
index 440d1066..d76d8971 100644
--- a/src/modules/Contrast/Module.js
+++ b/src/modules/Contrast/Module.js
@@ -15,9 +15,27 @@ module.exports = function Contrast(options, UI) {
 
     var step = this;
 
-    function extraManipulation(pixels) {
-      pixels = require('./Contrast')(pixels, options.contrast);
-      return pixels;
+    let contrast = options.contrast;
+
+    contrast = Number(contrast);
+    if (contrast < -100) contrast = -100;
+    if (contrast > 100) contrast = 100;
+    contrast = (100.0 + contrast) / 100.0;
+    contrast *= contrast;
+
+    function changeContrast(p){
+      p -= 0.5;
+      p *= contrast;
+      p += 0.5;
+      p *= 255;
+      p = Math.max(0, p);
+      p = Math.min(p, 255);
+      return p;
+    }
+
+    function changePixel(r, g, b, a) {
+      
+      return [changeContrast(r / 255), changeContrast(g / 255), changeContrast(b / 255), a];
     }
 
     function output(image, datauri, mimetype, wasmSuccess) {
@@ -27,7 +45,7 @@ module.exports = function Contrast(options, UI) {
     return require('../_nomodule/PixelManipulation.js')(input, {
       output: output,
       ui: options.step.ui,
-      extraManipulation: extraManipulation,
+      changePixel: changePixel,
       format: input.format,
       image: options.image,
       callback: callback,